#include<bits/stdc++.h>
using namespace std;
int main()
{
	double x1, x2, x3, y1, y2, y3;
	cin>>x1>>y1>>x2>>y2>>x3>>y3;
	if((x1-x2)*(y1-y3) == (x1-x3)*(y1-y2))
		cout<<"NO";
	else
		cout<<"YES";
	return 0;
}

